All the regulars are aware of it but acting like it is some cosmic occurrence when in fact it is a minor prank that C-D deploys to random visitors to keep things interesting in this section of the forum.
OK, I was kidding...or may be not?
On top of what others said, you might also want to check your "Pointer Options" tab (and "Wheel" tab if you have one) in the Mouse properties: START > RUN > main.cpl > OK